RCgothic

Well first off they were usually designed with redundant steam relief valves to stop that happening. Of the fifteen boiler explosions in the UK in the 20th century, only two were failures of the boiler barrel due to incorrectly assembled relief valves (overpressure). Thirteen were due to weakening of the firebox caused by low water level, which is not quite so spectacular. Low water level is caused by either operator error or faulty water level gauges.

0922 BST. Think I'll stick this one on as a short break from work!

Yet another reason SRBs have no business being anywhere near a man rated launcher.

The engine bells shouldn't be too difficult to replace I don't think.

Good call, although CRS-16 wasn't a total loss.

I remember the sea looked pretty rough after the landing. Not surprised nobody could board to make safe if octagrabber wasn't compatible. Still sad though. This the first loss of a block 5?

There's no reason why there couldn't be a reserve for a deorbit burn once payload insertion is complete.

So both second stages are undersized. The core stage is oversized but too anaemic in terms of thrust. And the boosters don't burn long enough. If core and boosters were able to put a sizeable payload in orbit without a second stage the problem wouldn't be half as bad. That would make it mission agnostic, just change what you stick on top of it. If I were designing a SHLV today it would probably look a lot like SA-513 that launched Skylab with flyback side boosters. Two and a half stages to orbit and whatever you like on top.

Stage and a half to not-quite-orbit is such a bizarre architecture.

This is not quite the while story, as you only get robbed of the full 9.81m/s per second if you're burning purely vertical. Once you start burning sideways gravity drag has less and less effect. This is a trigonometric effect. Your thrust makes up the hypotenuse. Gravity drag is vertical. Your desired velocity vector is the difference.

SLS won't be building LOP-G though. It can't co-manifest substantial enough payloads prior to block 2. So we're talking about 3rd party boosters anyway. Falcon can send both the payloads and the crew, separately, within a short enough space of time to be useful. Dragon2 will be able to go to the moon.

Extended deep space operations are pretty pointless if the booster is incapable of taking crew anywhere that requires them. The only difference between extended deep space operations and extended LEO operations is risk to crew.

We do need to launch on the timescales Apollo did because that enables rendezvous mission architectures. Without those we are never going beyond the earth moon system and we are never establishing a significant lunar presence.

We never *will* be ready for the moon or mars or even just significant orbital presence unless and until we have a booster capable of doing the job. Of lifting substantial payloads and performing the required rendezvous mission architectures. Want to forget the competition? Fine. They're forgotten. SLS is *still* not the booster that advances manned spaceflight. Its most advanced form can barely recreate Apollo at 1/4 of the flight cadence.

Yes, payload integration happens after static fire so that if the booster explodes it doesn't take the payload with it, as happened with AMOS 6.